We have developed and characterized a more native energy-transducing lipososmal system that utilizes purple membrane fragments (PM) of Halobacterium salinarium which contain intact trimer units of bacteriorhodopsin (BR) rather than depolymerized monomers obtained from the PM by extensive exposure to Triton as is commonly done. In order to accomplish this goal, we have developed a computer-based system using new analytical methodology (J. Biochem. Biophys. Meth. (1996) 33:89-104). The technique for liposome formation is a modification of the reversed phase evaporation procedure of Rigaud, developed for BR monomers. The new PM-liposomal system is capable of incorporating relatively high levels (compared to previous systems) of BR. Initial H+-pumping rates and levels of total accumulation were 530 neq H+ per min per mg BR and 400 neq/mg BR in the monomer liposomal system and 3300 neq H+ per min per mg and 2000 neq/mg BR in the PM liposomal system. Other differences between the monomer BR and PM liposomal systems were found. delta pH was constant as the BR content was increased in the monomer system but increased steadily in the PM system. Similarly, delta pH stayed constant in the monomer system as internal buffer strength was increased but in the PM system, delta pH increased with increasing internal buffer strength. Ordinarily, an increase in internal buffer capacity would be expected to decrease the magnitude of delta pH. The findings of an increase suggest an active role for buffer in the H+ transport process. A paradox regarding delta psi formation was found. The initial (1st sec) rate of H+ pumping was increased up to 15 fold by the presence of valinomycin and K+. This is explained by the fact that a delta psi electrically opposes transport of the H+ cation and valinomycin plus K+ electrically neutralizes the 1. However, little or no delta psi could be measured using traditional probes for the measurement such as thiocyanate and Oxanols V and VI. One possible explanation of this mystery might involve some local delta psi gradient, which is shielded from measurement by the probes for a global delta psi. Attempts will be made to try to resolve this dilemma. The possibility of local delta mu H+ phenomena have long intrigued workers in this field.